1. Field
This document relates to a method for manufacturing an in-plane switching mode liquid crystal display, and more particularly to, a method for manufacturing an in-plane switching mode liquid crystal display, which can prevent the problem of bubble generation caused by an Ag dot during the attachment process of a liquid crystal panel and a cover substrate, and improve the yield of an Ag dot process.
2. Related Art
Recently, with the development of various portable electronic devices, such as mobile phones, PDAs, notebook computers, etc., a light, thin, small flat panel display device has been in great demand. Research and development are actively conducted for the flat panel display devices, such as an LCD, a PDP (Plasma Display Panel), an FED (Field Emission Display), etc. Among these devices, the LCD attracts much more attention because of its simple mass-production technique, easy driving system, and implementation of a high picture quality.
There are various display modes, such as TN and VA, for the LCD device according to arrangement of liquid crystal molecules. Currently, a TN (twisted pneumatic) mode LCD device is being generally utilized because of short response time and low driving voltage. When a voltage is applied to the TN mode LCD device, liquid crystal molecules aligned to be horizontal to a substrate are aligned to be nearly perpendicular to a surface of the substrate. Accordingly, there is a problem in that a viewing angle is narrowed by refractive anisotropy of the liquid crystal molecules in applying of the voltage.
In order to solve this problem, LCD devices of in-plane switching modes having wide viewing angle characteristics have been proposed.
FIG. 1a is a view showing a structure of a conventional in-plane switching mode liquid crystal display. FIG. 1b is a view showing a conventional method for manufacturing an in-plane switching mode liquid crystal display.
Referring to FIG. 1a, the in-plane switching mode liquid crystal display 1 comprises a liquid crystal panel LP comprising a TFT array substrate 3 having thin film transistors, a common electrode, pixel electrodes, and a driving IC 4, a color filter substrate 5 having rear ITO and color filters, and a liquid crystal layer (not shown) interposed between the substrates. A lower polarizer 7 is disposed under the TFT array substrate 3, and an upper polarizer 8 is disposed on top of the color filter substrate 5.
An Ag dot 10 connecting the rear ITO of the color filter substrate 5 and the ground of the TFT array substrate 3 is disposed on the bonded edge of the TFT array substrate 3 and the color filter substrate 5. And, a cover substrate 12 is attached and disposed on the liquid crystal panel LP through an OCA (Optical Clear Adhesive) film 13.
A process for forming the Ag dot is performed by a manual or automatic process. In particular, in the manual process, the size of the Ag dot 10 may be increased depending on a manufacturer. Also, in the automatic process, the cohesiveness of Ag paste is made low in order to prevent a nozzle for applying the Ag dot from being blocked. Due to this, the size of the Ag dot may be increased after the application of the Ag paste.
Accordingly, as shown in FIG. 1b, the Ag dot 10 intrudes into the area to which the cover substrate 12 is bonded, thus causing the problem that bubbles are produced between the OCA film 13 and the upper polarizer 8. Therefore, the yield of the bonding process of the cover substrate and the liquid crystal panel and the Ag dot process is low.